Adhesive applying device for shoe lasting machines



1969 G. c. BARTON ETAL 3,481,303

ADHESIVE APPLYING DEVICE FOR SHOE LASTING MACHINES Filed Noi. 28. 196'? 2 Sheets-Sheet 1 [n-ven fora George 6. Barton Philip Reader- By zhei/"Azzorney Dec. 2, 969 G. c. BARTON ETAL 3,481,308

ADHESIVE APPLYING DEVICE FOR SHOE LASTING MACHINES Filed Nov. 28, 1967 2 Sheets-Sheet 2 United States Patent O 3,481,308 ADHESIVE APPLYING DEVICE FOR SHOE LASTING MACHINES George C. Barton and Philip Reader, Leicester, England, assignors to USM Corporation, Flemington, N.J., a corporation of New Jersey Filed Nov. 28, 1967, Ser. No. 686,090 Claims priority, application Great Britain, Apr. 18, 1967, 17,720/ 67 Int. Cl. B05c 5/02; B05b 1/14, 7/26 US. Cl. 118317 Claims ABSTRACT OF THE DISCLOSURE An adhesive applying device for shoe lasting machines with outlet openings leading from a chamber disposed at the end of a bore having a tube therein forming an annular passage in the bore, the tube being connected to a source of adhesive for admitting a charge of adhesive to said chamber, and said passage being connected to a source of pressurized air for forcing the adhesive from the chamber through the outlets.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to improvements in devices for applying adhesive to an insole and an upper assembled on a form in a shoe lasting machine.

Description of the prior art There is disclosed, in application for United States Patent, Ser. No. 627,335 filed Mar. 31, 1967, now US. Patent No. 3,386,114 issued June 4, 1968, a machine for lasting shoes. The machine includes a device in which adhesive is fed into a metering chamber also having an air operated plunger for forceably ejecting the adhesive from the chamber and outlet openings onto an insole and/or the lasting margin of a shoe upper. While this device operates satisfactorily it includes rather complex and relatively expensive mechanisms.

The adhesive and pressurized air is admitted to the chamber by means of a common bore. While the device formed an improvement over that shown in'said patent by virtue of a greatly simplified mechanism, it was found that an undesired mixing of adhesive and air occurred as the adhesive was blown from the nozzle. This resulted in a frothing of the adhesive which tended to form a curtain between the lasting margin of the upper and the lasting margin of the insole with an adverse aifect on the bond between the insole and the lasting margin of the upper.

SUMMARY OF THE INVENTION Accordingly it is an object of the present invention to overcome the objections inherent in the above devices. The adhesive applying device described herein and forming the present invention is provided with means for separating the adhesive and pressurized air so to avoid or at least minimize undesirable mixing when the adhesive is blown from the device. To this end a chamber having outlet openings is disposed at the end of a bore in which a tube forms an annular passage with the bore and also ends at the chamber. The tube is connected to a source of adhesive for feeding a charge of adhesive into the chamber, and the passage is connected to a source of pressurized air for blowing the adhesive from the chamber through the openings. In this manner undesirable mixing of air and adhesive is avoided.

A further feature of the invention provides in the end of the tube a plug having a small orifice which prevents 3,481,308 Patented Dec. 2, 1969 ice dribbling of adhesive from the tube when feeding of the adhesive through the tube is ended.

The above and other objects of the invention will now be described with reference to the drawings and thereafter pointed out in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown an illustrative adhesive applying device embodying the invention.

The device includes a body 12 having a bore 14 which is sealed at its upper end by a cap 16. Fixed in the cap is a tube 20 which depends in the bore and forms therebetween an annular passage 21. A plug 22 in the lower end of the tube has a relatively small bore 24 for a purpose which will appear. A nozzle foot 18 is secured to the lower end of the body 12 and is provided with a recess 26 forming a chamber at the upper side of which both the tube and annular passage terminate. The cap 16 is provided with a lug 34 which receives an adjusting screw 38 also mounted in the bifurcated end of an arm 33 which locates the device in the machine in the same general manner as an arm of said patent.

The machine is provided with a source of adhesive comprising a pressurized adhesive container 25 shown diagrammatically in FIG. 3. At a predetermined time in the machine cycle a valve 27 is opened for the flow of adhesive under pressure from the container through a conduit 35, tube 20 and bore 24 into the chamber 26. The valve 27 is adapted to remain open a predetermined time to feed a desired quantity of adhesive into the chamber. A heating cartridge 28, FIG. 1, mounted in the body 12 maintains the adhesive in molten condition if thermoplastic type of adhesive is used. After the valve 27 is closed a valve 29, FIG. 3, is opene to admit air under pressure to the annular passage 21 through an inlet 30 in the body 12, thereby blowing the molten adhesive in the chamber through a plurality of outlet openings 32 in the nozzle foot 18.

As shown particularly in FIGS. 1 and 2, the foot 18 extends lengthwise of the shoe which is positioned against it in operative position in the machine. For purposes of illustration the nozzle foot 18 is also used as a holddown member against which the insole bottom of the shoe is held. It will be obvious that the nozzle foot could take other forms such, for example, as a nozzle 172 shown in United States Patent No. 3,271,800, without departing from the scope of the invention. The outlet openings 32 in the nozzle foot 18 extend through opposite side walls of the chamber 26 as well as through a curved rear wall thereof. The openings are disposed to direct adhesive downwardly toward the region of the edge of the insole around the heel end and also along opposite side portions of the lasting margin of the upper.

Referring to FIG. 1, a shoe S on a last L is shown in operative position supported against the foot 18 of the adhesive applying device. The upper U of the shoe may be upstanding or partially overlying the insole as in FIG. 1 as a consequence of a previous backpart molding operation. When air under pressure is admitted to the chamber 26, the adhesive therein is blown out through the outlets 32 which direct it between the insole I and the lasting margin M of the upper.

When the valve 29 is open an air reservoir 31, FIG. 3, charged at above atmospheric air pressure, is discharged into the chamber 26 to completely scavenge the adhesive from the chamber. The plug 22 in the tube minimizes dribbling of adhesive from the tube until communication is again established between the container 25 and the tube. At that time the pressure acting on the adhesive is above atmospheric pressure and forces adhesive out of the tube through the bore 24 in the plug.

A typical pneumatic control circuit suitable for operating the present adhesive applying device in conjunction with a lasting machine will now be described with reference to FIG. 3. Depression of a treadle (not shown) effects movement of a jack to move the shoe against the nozzle foot 18 generally in the manner disclosed in said patent. In order to accommodate the adhesive applying device constituting the holddown, the pneumatic circuit is constructed so that on depression of the treadle the valve 27 is opened to admit adhesive to the chamber 26 in the device. However, the machine operator may wish to release the treadle at this stage in order to readjust the shoe and again depress the treadle to return the shoe into engagement with the foot 18. So that the chamber is not again charged with adhesive the pneumatic circuit is arranged so that adhesive is admitted to the chamber only once during each complete operating cycle of the machine.

Depression of the treadle, in addition to effecting movement of the machine jack, effects operation of an air operated valve 40 to direct air under pressure through a line 42 to open a valve 44. On opening the valve 44, air pressure which is normally holding valve 27 closed is redirected to open it and thus effect flow of adhesive under pressure through tube 20 to the chamber 26 of the adhesive applying device. Operation of the valve 40 also effects charging of an air reservoir 46 through a variable restrictor 47. At a certain air pressure of the reservoir 46 a valve 48 is shifted to close the line 42, and connect the valve 44 to exhaust, whereupon the valve 44 is spring re turned to its closed condition in which it directs air under pressure to close the valve 27. The valve 48 is held to close the line 42 until the completion of a complete operative cycle of the machine when an air signal resets the valve 40 and thus connects the reservoir 46 to exhaust whereupon the valve 48 is spring returned to its normal condition. Thus the valve 48 prevents the chamber being charged with adhesive more than once during a complete operative cycle of the machine. The variable restrictor 47 times the shifting of the valve 48 to close the line 42 and thus controls the quantity of adhesive supplied to the chamber.

When the air supply to the machine is connected therewith the air reservoir 31 is charged at above atmospheric pressure. Further depression of the treadle, following jacking of the shoe in the machine into its operative position against the foot 18 and charging of the chamber with adhesive, initiates operation of lasting instrumentalities of the machine and also effects opening of the valve 29. This disconnects the reservoir 31 from its air supply and puts the reservoir in communication through inlet with the chamber 26 and thus causes the adhesive to be blown therefrom by the air escaping from the reservoir.

FIG, 4 shows the adhesive applying device fitted with a modified form of nozzle foot. This foot is readily removable from the body of the adhesive applying device so that it can be immersed in a solvent for the adhesive to clean the foot when desired. To this end a nozzle foot 118 is provided with outlet passages corresponding to the passages 32 of the foot 18 above described. A portion 120 projecting forwardly from an upstanding rear wall 122 of the foot has an inclined under surface 124 adapted to fit over a mating surface 125 on a body portion 112 of the device. An upstanding front portion 128 of the foot carries a pointed screw 130 which is received in a conical recess 132 in the body portion. Tightening of the screw results in the foot 118 being wedged upwardly to provide a seal between an upper face of the foot around a recess 126 (corresponding to the recess 26 of the foot 18 above referred to) in the foot 118 and a lower end face of the body portion 112. Loosening of the screw 130 enables the foot 118 to be quickly removed from the adhesive applying device for cleaning.

Having thus described our invention, what we claim as new and desired to secure by Letters Patent of the United States is:

1. In a machine for lasting a shoe comprising an upper and an insole assembled on a form and having a nozzle for applying adhesive on the insole and/or the margin of the upper, said nozzle having a chamber for receiving adhesive and passageways leading from the chamber toward the insole and/or upper margin surfaces to which the adhesive is to be applied, the improvement comprising a member on which the nozzle is formed and having a bore terminating at the chamber, a tube in the bore of lesser diameter forming an annular passage in the bore around the tube, said tube being connected at one end to a source of adhesive and terminating at the other end at said chamber, an inlet in the bore leading into said passageway from a source of pressurized air, means for feeding a charge of adhesive through the tube into the chamber, and means thereafter effective to admit pressurized air through the inlet and annular passage to the chamber to eject adhesive from the chamber without substantial mixing of the air with the adhesive.

2. A machine according to claim 1 in which the tube end adjacent to the chamber is provided with an outlet opening of smaller diameter than the tube.

3. A machine according to claim 1 in which the tube is provided with a plug adjacent to the chamber having an orifice smaller than the tube to prevent adhesive from dribbling from the tube when feed of the adhesive is stopped.

References Cited UNITED STATES PATENTS 4/1942 Murphy l18323 X 5/1954 Kamborian 118323 X US. Cl. X.R. 

